Reduce gear ratio

Transmit power between driver and driven gears

Reduce spindle speed

Increase spindle speed

Major dia of work

Pitch

Root dia of work

Angle of thread

Driver 60 driven 50

Driver 40 driven 20

Driver 85 teeth driven 60 teeth

Driver 100 teeth driven 25 teeth

Driver 40 teeth Driven 20 teeth

Driver 50 teeth Driven 60 teeth

Driver 80 teeth Driven 25 teeth

Driver 60 teeth Driven 35 teeth

Affect gear ratio

Does not affect gear ratio

Change the speed

Easy to engage